Method, device and system for performing wireless communication in wireless communication system

ABSTRACT

A method, device and system for performing wireless communication in a wireless communication system. The wireless communication system includes a low power node and a macro base station with common baseband and user equipment, and the user equipment communicates with the low power node and the macro base station via a plurality of component carriers. The method includes: receiving, by the user equipment, a downlink signal transmitted by the low power node and the macro base station; and transmitting uplink signals to the low power node and the macro base station, wherein the method further includes: transmitting all first uplink signals of the uplink signals to the low power node as a receiving node. According to the method, device and system, it is possible to improve the efficiency of uplink power control of a terminal and/or reduce the burden for uplink control channel transmission of a macro cell.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation application which claims thebenefit of priority under 35 U.S.C. § 120 of U.S. patent applicationSer. No. 15/481,832, filed Apr. 7, 2017, which is a division of U.S.patent application Ser. No. 14/786,041, filed Oct. 21, 2015, which is aNational Stage of PCT filing PCT/CN2014/077786, filed May 19, 2014, andclaims priority to Chinese Patent Application 201310202975.8, filed inthe Chinese Patent Office on May 28, 2013, the entire contents of eachare incorporated herein by reference.

FIELD OF THE INVENTION

The disclosure relates to the technical field of wireless communication,and particularly to a method for performing wireless communication in awireless communication system, a wireless communication device and awireless communication system.

BACKGROUND OF THE INVENTION

This section provides background information related to the disclosure,which is not necessarily prior art.

Carrier aggregation before LTE (Long Term Evolution) Rel-11 is carrieraggregation of a single base station node. An aggregated carrier of aterminal is constituted of one primary component carrier and at leastone secondary component carrier. In a FDD (Frequency Division Duplex)mode, association between a downlink primary component carrier and anuplink primary component carrier is determined via a SIB2 (SystemInformation Block 2) message. A PUCCH (Physical Uplink Control Channel)signal is transmitted on the uplink primary component carrier. Normally,only one uplink component carrier performs uplink data transmission.Change of the primary component carrier implies occurrence of a handoffbehavior.

In a case where the carrier aggregation is performed between basestations, if a macro base station and a low power node are not in commonbaseband, then uplink carrier aggregation will occur, and the originalprimary component carrier setting and association rules are still valid.Since component carriers of the macro base station are mainly used fordata transmission related to mobility control, the primary componentcarriers may include a downlink component carrier of the macro basestation. If the uplink primary component carrier is still associated inaccordance with the SIB2, then it cannot assist the macro base stationin performing PUCCH shunting to alleviate the burden for an uplinkcontrol channel of a macro cell in a case where the base station and thelow power node perform common baseband transmission. In addition, whenthe macro base station and the low power node perform CoMP (CoordinatedMulti-Point) transmission, and particularly for a case where the macrobase station serves as an uplink receiving node, it is unable to performaccurate power control. Further, a solution that takes the macro basestation as a receiving node to perform uplink power control is notbeneficial to reduce energy consumption of UE (User Equipment).

SUMMARY OF THE INVENTION

This section provides a general summary of the disclosure, rather than athorough disclosure of the full scope or all features thereof.

The disclosure aims at providing a method for performing wirelesscommunication in a wireless communication system, a wirelesscommunication device and a wireless communication system, which canimprove the efficiency of uplink power control of a terminal and/orreduce the burden for uplink control channel transmission of a macrocell.

According to one aspect of the disclosure, a method for performingwireless communication in a wireless communication system is provided.The wireless communication system includes a low power node and a macrobase station with common baseband and user equipment, and the userequipment communicates with the low power node and the macro basestation via a plurality of component carriers. The method includes:receiving, by the user equipment, a downlink signal transmitted by thelow power node and the macro base station; and transmitting uplinksignals to the low power node and the macro base station, wherein themethod further includes: transmitting all first uplink signals of theuplink signals to the low power node as a receiving node.

According to another aspect of the disclosure, a wireless communicationdevice is provided. The wireless communication device is used tocommunicate with a low power node and a macro base station with commonbaseband via a plurality of component carriers, and includes: areceiving unit adapted to receive a downlink signal transmitted by thelow power node and the macro base station; a transmitting unit adaptedto transmit uplink signals to the low power node and the macro basestation; and a control unit adapted to control the transmitting unit totransmit all first uplink signals of the uplink signals to the low powernode as a receiving node.

According to another aspect of the disclosure, a wireless communicationsystem is provided. The wireless communication system includes: a macrobase station; a low power node in common baseband with the macro basestation; and a wireless communication device according to thedisclosure, which communicates with the low power node and the macrobase station via a plurality of component carriers.

According to another aspect, a communication device operational in acommunication system including a first node and a second node, thecommunication device comprising: circuitry configured to causecommunication with the first node and the second node based on carrieraggregation, the communication including: setting a downlink componentcarrier associated with the first node a downlink primary componentcarrier, and setting an uplink component carrier associated with thesecond node as an unlink primary component carrier for transmittingPhysical Uplink Control Channel (PUCCH), wherein the communicationincludes transmitting, using the circuitry, an uplink control signalingvia the uplink primary component carrier associated with the secondnode. The communication can also include, prior to the setting of theuplink component carrier, releasing association of the downlink primarycomponent carrier from the uplink primary component carrier. The firstnode may be a macro base station and the second node may be a low powernode (LPN). Further, the first node may operate at a first frequency,and the second node may operate at a second frequency greater than thefirst frequency.

The communication can include transmitting, using the circuitry, datapackets via the uplink primary component carrier associated with thesecond node. Optionally, the communication includes transmitting, usingthe circuitry, Physical Uplink Shared Channel (PUSCH) signals via theuplink primary component carrier associated with the second node. Asanother option, the communication includes transmitting, using thecircuitry, all uplink control signaling via the uplink primary componentcarrier associated with the second node. And in another option,communication includes transmitting, using the circuitry, uplink controlsignaling via the uplink primary component carrier associated with thesecond node to control transmissions between the device and the firstnode.

The communication can also include receiving, by the circuitry,designation information regarding the uplink primary component carriervia one of Radio Resource Control (RRC) signaling, Media Access Control(MAC) signaling, or physical layer signaling. Further, optionally, thecommunication includes aggregating multiple component carriers for thesecond node, and receiving, using the circuitry, information regardingdesignation of the uplink primary component carrier via one of RadioResource Control (RRC) signaling, Media Access Control (MAC) signaling,or physical layer signaling.

According to another aspect, a wireless communication method comprisingperforming communication, using a processor, with a first node and asecond node based on carrier aggregation, said communication includingsetting a downlink component carrier associated with the first node as adownlink primary component carrier, and setting an uplink componentcarrier associated with the second node as an uplink primary componentcarrier for transmitting Physical Uplink Control Channel (PUCCH),wherein the communication includes transmitting an uplink controlsignaling via the uplink primary component carrier associated with thesecond node. The communication can also include, prior to the setting ofthe uplink component carrier, decoupling the downlink primary componentcarrier from the uplink primary component carrier. The first node can bea macro base station, and the second node can be a low power node (LPN).

The communication can include transmitting data packets via the uplinkprimary component carrier associated with the second node. Optionally,the communication can include transmitting uplink control signaling viathe uplink primary component carrier associated with the second node tocontrol transmissions between the processor and the first node. Thecommunication can also include receiving designation informationregarding the uplink primary component carrier via one of Radio ResourceControl (RRC) signaling, Media Access Control (MAC) signaling, orphysical layer signaling. Optionally, the communication includestransmitting Physical Uplink Shared Channel (PUSCH) signals via theuplink primary component carrier associated with the second node.

According to another aspect, a wireless communication device forcontrolling uplink transmission power for Coordinate Multi-Point (CoMP)transmission of a first node and a second node on a first componentcarrier at a first frequency, the device comprises: circuitry configuredto receive a downlink signal from the second node on a second componentcarrier at a second frequency different from the first frequency,determine a first downlink path loss associated with receipt of thedownlink signal from the second node on the second component carrier atthe second frequency, estimate a second downlink path loss associatedwith the second node performing the CoMP transmission on the firstcomponent carrier at the first frequency based on the determined firstdownlink path loss, and estimate a first uplink path loss of a firstuplink signal output from the device to the second node on the firstcomponent carrier at the first frequency based on the estimated seconddownlink path loss, to compensate uplink signal transmission power forthe CoMP transmission. The uplink signal may be one of a Physical UplinkControl Channel (PUCCH) signal, Physical Uplink Shared Channel (PUSCH)signal, and a Sounding Reference Signal (SRS).

The circuitry may be configured to compensate the uplink signaltransmission power for CoMP transmission to the second node on the firstcomponent carrier at the first frequency based on the first uplink pathloss. Further, the circuitry can be configured to compensate uplinksignal transmission power for CoMP transmission to the first node on thefirst component carrier at the first frequency based on determination ofa third downlink path loss associated with receipt of a downlink signalfrom the first node on the first component carrier at the firstfrequency, and determination of a second uplink path loss of a seconduplink signal output from the device to the first node on the firstcomponent carrier at the first frequency based on the third downlinkpath loss. Optionally, when the CoMP transmission of the first node andthe second node is according to CoMP scenario 4, receiving powerassociated with the first node is obtained by adding linearly detectedreference signal receiving power of cell-specific reference signal ofthe first and second nodes to receiving power associated with the secondnode. Alternatively, when the CoMP transmission of the first node andthe second node according to CoMP scenario 3, receiving power associatedwith the first node is obtained by subtracting linearly detectedreference signal receiving power of cell-specific reference signal ofthe first and second nodes from receiving power associated with thesecond node.

According to yet another aspect a wireless communication method forcontrolling uplink transmission power for Coordinate Multi-Point (CoMP)transmission of a first node and a second node on a first componentcarrier at a first frequency, comprises: receiving a downlink signalfrom the second node on a second component carrier at a second frequencydifferent from the first frequency, determining a first downlink pathloss associated with receipt of the downlink signal from the second nodeon the second component carrier at the second frequency, estimating asecond downlink path loss associated with the second node performing theCoMP transmission on the first component carrier at the first frequencybased on the determined first downlink path loss, and estimating a firstuplink path loss of a first uplink signal output from the device to thesecond node on the first component carrier at the first frequency basedon the estimated second downlink path loss, to compensate uplink signaltransmission power for the CoMP transmission.

By transmitting all first uplink signals of the uplink signals to thelow power node as a receiving node, the method for performing wirelesscommunication in a wireless communication system, the wirelesscommunication device and the wireless communication system according tothe disclosure can improve the efficiency of uplink power control of aterminal and/or reduce the burden for uplink control channeltransmission of a macro cell.

Further applicable areas will be apparent from the description providedherein. The description and specific examples in the summary are onlyfor the purpose of illustration, rather than limiting the scope of thedisclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompany drawings described here are only for the purpose ofillustrating the selected embodiments rather than all possibleembodiments, and are not intend to limit the scope of the disclosure. Inthe accompanying drawings:

FIG. 1 is a schematic diagram illustrating a scenario of carrieraggregation between base stations;

FIG. 2 is a flowchart of a method for performing wireless communicationin a wireless communication system according to an embodiment of thedisclosure;

FIG. 3 is a schematic diagram illustrating a common baseband CoMP(Cooperated Multi-Point) transmission in a heterogeneous network;

FIG. 4 is a flowchart of a method for performing wireless communicationin a wireless communication system according to another embodiment ofthe disclosure;

FIG. 5 is a flowchart of a method for performing wireless communicationin a wireless communication system according to another embodiment ofthe disclosure;

FIG. 6 is a block diagram illustrating a wireless communication systemaccording to an embodiment of the disclosure; and

FIG. 7 is a block diagram of an exemplary structure of a general-purposepersonal computer in which a method for performing wirelesscommunication in a wireless communication system according to anembodiment of the disclosure can be implemented.

Although the disclosure is liable to various modifications andalternations, specific embodiments thereof have been shown as examplesin the accompany drawings and are described in detail herein. However,it should be understood that, the description of the specificembodiments herein does not intend to limit the disclosure to thespecific forms as disclosed. On the contrary, the disclosure aims atcovering all modifications, equivalents and alternations within thespirit and scope of the disclosure. It should be noted that,corresponding reference numbers indicate corresponding componentsthroughout several accompany drawings.

DETAILED DESCRIPTION OF THE INVENTION

Examples of the disclosure are now described more fully with referenceto the accompany drawings. The following description is essentiallyexemplary, but not intended to limit the disclosure, applications anduses.

Exemplary embodiments are provided to make the disclosure more detailedand sufficiently convey the scope thereof to those skilled in the art.Numerous specific details, such as examples of a specific component, adevice and a method, are illustrated to provide a thorough understandingof the embodiments of the disclosure. It will be apparent to thoseskilled in the art that, the exemplary embodiments can be implemented indifferent ways without using the specific details, and the exemplaryembodiments should not be interpreted as limiting the scope of thedisclosure. In some exemplary embodiments, well-known processes,well-known structures and well-known technologies are not described indetail.

In the scenario shown in FIG. 1, a macro base station 1 has a widecoverage area which is referred as to a macro cell, and a low power node2 has a narrow coverage area which is referred as to a small cell. Themacro base station 1 has a frequency point of, for example, 2 GHz, andthe low power node 2 has a frequency point of, for example, 3.5 GHz.Carrier aggregation may be performed between the macro base station 1and the low power node 2. The macro base station 1 may be, for example,directly connected to the low power node 2 via an optical fiber 4, sothat the macro base station 1 and the low power node 2 are in commonbaseband. UE (user equipment) 3 may communicate with both the macro basestation 1 and the low power node 2 via multiple component carriers.

As an example, the UE 3 has performed carrier aggregation between nodesof the macro base station 1 and the low power node 2, and the aggregatedcomponent carriers include a carrier a and a carrier b. Specifically,the low power node 2 and the macro base station 1 perform CoMP(Cooperated Multi-Point) transmission for the UE 3 on the componentcarrier a, and the low power node separately serves the UE 3 on thecarrier b.

As another example, the UE 3 may communicate with the macro base station1 via a component carrier c, and communicate with the low power node 2via a component carrier d. A carrier aggregation may be performed forthe component carrier c and the component carrier d (carrier aggregationbetween nodes).

In the prior art, in a case where a carrier aggregation is performedbetween the macro base station 1 and the low power node 2, originalprimary component carrier setting and the association rules are stillvalid. For example, in a FDD mode, association with an uplink primarycomponent carrier may be performed via SIB2 transmitted by a downlinkprimary component carrier. Alternatively, in the absence of SIB2content, the UE 3 may acknowledge an uplink primary component carriervia a default frequency point spacing between a downlink primarycomponent carrier and the uplink primary component carrier associatedwith the downlink primary component carrier. In a TDD (Time DivisionDuplex) mode, a transmission function of a default downlink primarycomponent carrier and a transmission function of an uplink primarycomponent carrier are performed on a same component carrier.

Since the component carriers of the macro base station 1 are mainly usedfor data transmission related to mobility control, the primary componentcarriers may include a downlink component carrier of the macro basestation 1. In this way, the primary component carriers will also includean uplink component carrier of the macro base station 1 based on theoriginal primary component carrier setting and the association rules.

In addition, when the UE 3 transmits uplink data on two or morecomponent carriers, in a case of limited power, if uplink transmissionpower exceeds maximum transmission power, then a case of discardinguplink SRS (Sounding Reference Signal)/PUCCH (Physical Uplink ControlChannel)/PUSCH (Physical Uplink Shared Channel) information may occur,thereby resulting in loss of the data transmission. Therefore, uplinkdata transmission is generally performed on the uplink primary componentcarrier as much as possible. Therefore, in the case that the macro basestation 1 and the low power node 2 perform common baseband transmissionas shown in FIG. 1, the low power node cannot assist the macro basestation 1 in performing PUCCH shunting to alleviate the burden for anuplink control channel of a macro cell. Further, a solution that takesthe macro base station 1 as a receiving node to perform uplink powercontrol is not beneficial to reduce energy consumption of the UE 3.

In order to alleviate the burden for an uplink control channel of themacro cell and reduce the energy consumption of the UE, an embodiment ofthe disclosure provides a method for performing wireless communicationin a wireless communication system, as shown in FIG. 2. The wirelesscommunication system includes, for example, the low power node 2 and themacro base station 1 with common baseband and the UE 3 as shown in FIG.1, and the UE 3 communicates with the low power node 2 and the macrobase station 1 via multiple component carriers.

As shown in FIG. 2, at step S210, user equipment receives a downlinksignal transmitted by the low power node and the macro base station. InFIG. 1, the communication of the UE 3 with the macro base station 1 andthe low power node 2 is schematically shown. For example, when the UE 3is within the coverage area of the macro base station 1 and also withinthe coverage area of the low power node 2, communication between themacro base station 1 and the UE 3 is performed via a C-plane (controlplane), and communication between the low power node 2 and the UE 3 isperformed via a U-plane (user plane).

Next, at step S220, uplink signals are transmitted to the low power nodeand the macro base station. For example, as shown in FIG. 1, the UE 3may transmit an uplink signal to the low power node 2, and may alsotransmit an uplink signal to the macro base station 1.

Finally, at step S230, all of first uplink signals of the uplink signalsare transmitted to the low power node as a receiving node. The firstuplink signals here may include, but are not limited to, a PUCCH signaland/or a PUSCH signal.

Different from a case that the PUCCH signal and the PUSCH signal areonly transmitted on a default uplink primary component carrier of themacro base station 1 in the prior art, the method according to anembodiment of the disclosure transmits all of the first uplink signals,including the PUCCH signal and/or the PUSCH signal, to the low powernode 2, to achieve shunting of the uplink signals, thereby alleviatingthe burden for an uplink control channel of the macro cell. In addition,considering that the distance between the UE 3 and the low power node 2is much shorter than the distance between the UE 3 and the macro basestation 1 in a general case, the low power node 2 taken as a receivingnode of some uplink signals may be beneficial to reduce energyconsumption of the UE 3.

When the carrier aggregation is performed between nodes of the low powernode 2 and the macro base station 1, the macro base station 1 sets adownlink component carrier thereof as a downlink primary componentcarrier. In this case, the method according to an embodiment of thedisclosure may release the association between the uplink primarycomponent carrier and the downlink primary component carrier. In otherwords, the original primary component carrier setting and theassociation rules are released. In this way, the PUCCH signal and thePUSCH signal will not be only transmitted on the default uplink primarycomponent carrier of the macro base station 1.

In this case, when the wireless communication system is a FDD system, anuplink component carrier of the low power node 2 may be set as theuplink primary component carrier. In this way, the PUCCH signal and thePUSCH signal that are only transmitted on the uplink primary componentcarrier are transmitted to the low power node 2, thereby achievingshunting of the uplink signals.

In another aspect, when the wireless communication system is a TDDsystem, the transmission function of the downlink primary componentcarrier may be performed by a downlink timeslot of a component carrierof the macro base station 1, and the transmission function of the uplinkprimary component carrier may be performed by an uplink timeslot of acomponent carrier of the low power node 2. In this way, the PUCCH signaland the PUSCH signal may also be transmitted to the low power node 2, toachieve shunting of the uplink signals.

In addition, if the UE 3 aggregates multiple component carriers on thelow power node 2, and, for example, the macro base station 1 does notoperate on these component carriers, then the macro base station 1 (orthe low power node 2) may inform the UE 3 of the uplink primarycomponent carrier on the low power node 2 via RRC (Radio ResourceControl) signaling, MAC (Media Access Control) signaling or DCI(Downlink Control Information) of physical layer. The UE 3 may know theuplink primary component carrier on the low power node 2 by receivingthe RRC signaling, the MAC signaling or DCI of the physical layer.Alternatively, the UE 3 may also select by default a component carrierwith highest or lowest frequency point from these component carriers asthe uplink primary component carrier of the UE 3 on the low power node2.

Further, when the carrier aggregation between the nodes of the low powernode 2 and the macro base station 1 is terminated, the macro basestation 1 (or the low power node 2) may inform to recover theassociation between the uplink primary component carrier and thedownlink primary component carrier via the RRC signaling, the MACsignaling or the DCI of the physical layer. The UE 3 may be informed torecover the association between the uplink primary component carrier andthe downlink primary component carrier by receiving the RRC signaling,the MAC signaling or the DCI of the physical layer. Alternatively, theUE 3 may also recover by default the association between the uplinkprimary component carrier and the downlink primary component carrier. Anuplink component carrier of the macro base station 1 is set as theuplink primary component carrier after the association between theuplink primary component carrier and the downlink primary componentcarrier is recovered.

In the following, illustration will be made by taking FIG. 1 as anexample. If the UE 3 shown in FIG. 1 aggregates a component carrier of 2GHz and a component carrier of 3.5 GHz, then since the small cell ismainly responsible for the uplink data transmission, the PUCCH signaland the PUSCH signal are substantially all transmitted on the componentcarrier of 3.5 GHz. In this case, the PUCCH signaling for uplinktransmission of the macro cell is to be integrated into an uplinkcomponent carrier (FDD)/an uplink timeslot (TDD) of 3.5 GHz. Meanwhile,for saving transmission power of the UE 3, uplink signaling interactionbetween the UE 3 and the macro base station 1 may also be transmitted onthe uplink component carrier of 3.5 GHz. This operation may be performedby default after entering a carrier aggregation state between basestations, and may also be performed by the downlink primary componentcarrier via RRC/MAC/physical layer signaling.

If the UE 3 shown in FIG. 1 aggregates two or more component carriers ona frequency hand of 3.5 GHz of the small cell, then the downlink primarycomponent carrier specifies the uplink primary component carrier via theRRC/MAC/physical layer signaling, or the network and the UE 3 select bydefault a component carrier with highest or lowest uplink frequencypoint from the aggregated carriers of the small cell as the uplinkprimary component carrier.

If the UE 3 shown in FIG. 1 terminates the carrier aggregation statebetween the base stations, then the downlink primary component carrierinforms the UE 3 to recover the SIB2 association between the uplinkprimary component carrier and the downlink primary component carrier viathe RRC/MAC/physical layer signaling, or the network and the UE 3automatically recover this association by fault.

FIG. 3 shows a topological diagram of common baseband CoMP transmissionin a heterogeneous network. In an independent cell ID coordination mode(i.e., a CoMP scenario 3) and a single frequency network coordinationmode (i.e. a CoMP scenario 4) as shown in FIG. 3, a function ofdecoupling a downlink transmitting point and an uplink transmittingpoint is supported. In this case, if the decoupling of the uplinkprimary component carrier and the downlink primary component carrier isnot performed, then the low power node may still be selected as anuplink target receiving node in accordance with accurate power control,to save transmission power of the uplink PUCCH and uplink PUSCH. In thisway, when the SRS is transmitted to the low power node and the macrobase station, the accurate power control is also required to ensurecorrectness in data reception and efficiency of the power consumption.

Original uplink power control performs processing based on a path lossof a downlink transmitting point. If it is in the CoMP scenario 4 (samesignals from multiple transmitting points are integrated), then it isundoubted that quality estimation of a downlink channel is too high,thereby resulting in that the path loss compensation power is too low,and further resulting in reduction of reception quality of uplinksignal. On the other hand, if the uplink transmission power is increaseddue to downlink interference of the low power node in the CoMP scenario3, then interference on the low power node will be further increased.

The inventor of the disclosure suggests that uplink power controladjustment parameters of the PUSCH and the PUCCH are derived based oncompensation of inter frequency measurement, thereby optimizingtransmission result of the whole uplink data.

In addition, in the LTE/LTE-A TDD system, the SRS may be used fordetermining timing advance of uplink transmission, and may also be usedfor estimating quality of a downlink channel according to thecharacteristic of reciprocity between an uplink channel and the downlinkchannel. The transmission power in the former case depends on thecollection of receiving nodes, but the transmission power in the lattercase depends on the collection of transmitting nodes. The inventor hasknown that fine adjustment may be performed by increasing power controlnumerical range of the SRS, to minimize the risk of standardized work.The inventor considers that a unity solution is required to solveoptimization problems of the uplink power control under these scenarios.

FIG. 4 shows a method for path compensation of uplink power controlaccording to an embodiment of the disclosure. The method as shown inFIG. 4 is applicable for a case that the macro base station and the lowpower node perform CoMP transmission on at least a first componentcarrier and the low power node further communicates with the userequipment via at least a second component carrier.

As shown in FIG. 4, at step S410, a coordination downlink path loss whenthe low power node performs the CoMP transmission for the user equipmenton the first component carrier is estimated with reference to a separatedownlink path loss occurred when the low power node transmits a downlinksignal separately for the user equipment on the second componentcarrier.

The separate downlink path loss may be obtained according to thetransmission power when the low power node transmits a CRS(Cell-Specific Reference Signal) separately and linearly detected RSRP(Reference Signal Receiving Power) of the CRS of the low power node.

Next, at step S420, based on the coordination downlink path loss, anuplink path loss of an uplink signal issued by the user equipment whichtakes the low power node as a target receiving node on the firstcomponent carrier is estimated, to perform uplink signal transmissionpower compensation.

FIG. 5 shows an example of a method for estimating an uplink path loss.Specifically, at step S510, linearly detected RSRP of a CRS of the lowpower node may be subtracted from transmission power when the low powernode transmits the CRS separately, to obtain a separate downlink pathloss. This may be expressed with the following expression (1).

PL_(LPN) ^(dB)=TxPower(LPN_CRS)^(dB)−10 log 10RSRP_(LPN)^(Linear)(CRS)  (1)

wherein PL_(LPN) ^(dB) indicates a path loss of the LPN (low power node)in decibels (dB);TxPower(LPN_CRS)^(dB) indicates the transmission power in dB when theLPN transmits the CRS separately; and10 log 10RSRP_(LPN) ^(Linear) (CRS) indicates the linearly detected RSRPof the CRS of the LPN.

Next, at step S520, considering a frequency interval between a carrierseparately transmitted by the low power node and a CoMP carrier, aheight of frequency point, a distance between a terminal and the lowpower node, historical statistics and other factors, a coordinationdownlink path loss ƒ(PL_(LPN) ^(dB)) occurring when the low power nodetransmits a downlink signal in a CoMP mode may be estimated based on theseparate downlink path loss PL_(LPN) ^(dB). A deviation value betweenthe separate downlink path loss PL_(LPN) ^(dB) and the coordinationdownlink path loss ƒ(PL_(LPN) ^(dB)) is related to working frequencypoints of the two carriers, a frequency offset, a transmissionenvironment of the low power node, a specific position of the terminalwithin the coverage area of the low power node and the like.

Thereafter, at step S530, an uplink path loss may be estimated based onthe coordination downlink path loss ƒ(PL_(LPN) ^(dB)), for example,according to the characteristic of reciprocity between an uplink channeland a downlink channel. The simplest treatment is that the uplink pathloss is considered as being equal to the coordination downlink path lossƒ(PL_(LPN) ^(dB)).

In this way, derivation of the uplink power control adjustmentparameters of an uplink signal which takes the low power node as atarget receiving node is completed based on the compensation of theinter frequency measurement, thereby optimizing the transmission resultof the whole uplink data. The uplink signal here may include a PUSCHsignal, a PUCCH signal, or a SRS.

Regarding the specific power compensation method, when the uplink signalis a PUSCH signal, for example, the compensation may be performed withthe following expression (2):

P=min{P _(max),10 log M+P _(0_PUSCH)(j)+α(j)PL+Δ_(TF)+ƒ(i)}  (2)

where P indicates closed-loop power of the PUSCH (i.e., power providedby a terminal to transmit a PUSCH signal);P_(max) indicates maximum power;M indicates the number of resource blocks (RB);P_(0_PUSCH)(j) indicates a power reference value set by high-levelsignaling, for reflecting a noise level of an uplink receiving terminal;α(j) indicates a path loss compensation coefficient;PL indicates the uplink path loss estimated by the method of thedisclosure;Δ_(TF) indicates a power offset; andƒ(i) indicates an adjustment value.

When the uplink signal is a PUCCH signal, for example, the compensationmay be performed with the following expression (3):

P=min{P _(max) ,P _(0_PUSCH)(j)+PL+h(n _(CQI) ,n_(HARQ))+Δ_(F_PUCCH)(F)+g(i)}  (3)

where P indicates closed-loop power of the PUCCH (i.e., power providedby a terminal to transmit a PUCCH signal);P_(max) indicates maximum power;P_(0_PUSCH)(j) indicates a power reference value set by high-levelsignaling, for reflecting a noise level of an uplink receiving terminal;PL indicates the uplink path loss estimated by the method of thedisclosure;h(n_(CQI), n_(HARQ)) indicates an offset of the transmission power ofthe PUCCH;Δ_(F_PUCCH)(F) indicates power offset of the transmission power of thePUCCH of another kind; andg(i) indicates an adjustment value.

When the uplink signal is a SRS, for example, the compensation may beperformed with the following expression (4):

P=min{P _(max) ,P _(SRS_OFFSET)+10 log M _(SRS) +P_(0_PUSCH)(j)+α(j)PL+Δ_(TF)+ƒ(i)}  (4)

where P indicates closed-loop power of the SRS (i.e., power provided bya terminal to transmit a SRS);P_(max) indicates maximum power;P_(SRS_OFFSET) indicates a power offset for the SRS;M_(SRS) indicates the number of resource blocks (RB) required by theSRS;P_(0_PUSCH)(j) indicates a power reference value set by high-levelsignaling, for reflecting a noise level of an uplink receiving terminal;α(j) indicates a path loss compensation coefficient;PL indicates the uplink path loss estimated by the method of thedisclosure;Δ_(F) indicates a power offset; andƒ(i) indicates an adjustment value.

The above expressions (2) to (4) are closed-loop power control formulasfor the PUSCH, the PUCCH and the SRS, respectively. For open-loop powercontrol, the power compensation may be performed with the followingexpression (5):

PSD_(Tx) =P ₀+α·PL  (5)

where PSD_(TX) indicates open-loop power;P₀ indicates a power reference value set by high-level signaling, forreflecting a noise level of an uplink receiving terminal;α indicates a path loss compensation coefficient; andPL indicates the uplink path loss estimated by the method of thedisclosure.

The derivation of the uplink power control adjustment parameters of anuplink signal which takes the low power node as the target receivingnode has been described above. In a case where the macro base station istaken as the target receiving node, the derivation of the uplink powercontrol adjustment parameters of an uplink signal may also be performed.

According to an embodiment of the disclosure, a coordination downlinkpath loss when the macro base station performs the CoMP transmission forthe user equipment on the first component carrier may be estimated basedon the coordination downlink path loss of the low power node.

Specifically, the receiving power of the low power node may be obtained,for example, according to transmission power when the low power nodetransmits a CRS (Cell-Specific Reference Signal), data or a CSI-RS(Channel State Information-Reference Signal) in the CoMP transmissionmode for the user equipment on the first component carrier and thecoordination downlink path loss of the low power node.

Further, the receiving power of the macro base station may be obtainedaccording to the linearly detected RSPS of the CRS of the low power nodeand the macro base station as well as the receiving power of the lowpower node.

Further, a coordination downlink path loss of the macro base station maybe obtained according to the transmission power when the macro basestation transmits the CRS in the CoMP transmission mode for the userequipment on the first component carrier and the receiving power of themacro base station.

Next, based on the coordination downlink path loss of the macro basestation, an uplink path loss of an uplink signal issued by the userequipment which takes the macro base station as the target receivingnode on the first component carrier may be estimated, to perform uplinksignal transmission power compensation.

The uplink signal here may also include a PUSCH signal, a PUCCH signalor a SRS. Of course, as mentioned above, if the PUCCH signal and thePUSCH signal that are only transmitted on the uplink primary componentcarrier are all transmitted to the low power node for achieving shuntingof the uplink signals, then an uplink signal which takes the macro basestation as the target receiving node may only include a SRS, to predictthe quality of a downlink channel of the macro base station according tothe reciprocity between an uplink channel and the downlink channel.

Regarding the specific method for estimating an uplink path loss of anuplink signal issued by the user equipment which takes the macro basestation as a target receiving node (which is referred to as “an uplinkpath loss of the macro base station” hereinafter), the expression (1)mentioned above may also be adopted. Specifically, linearly detectedRSRP of a CRS of the low power node 10 log 10RSRP_(LPN) ^(Linear)(CRS)may be firstly subtracted from transmission power TxPower(LPN_CRS)^(dB)when the low power node transmits the CRS separately, to obtain aseparate downlink path loss PL_(LPN) ^(dB) of the low power node.

Next, considering a frequency interval between a carrier separatelytransmitted by the low power node and a CoMP carrier, a height offrequency point, a distance between a terminal and the low power node,historical statistics and other factors, a coordination downlink pathloss ƒ(PL_(LPN) ^(dB)) occurring when the low power node transmits adownlink signal in a CoMP transmission mode may be estimated based onthe separate downlink path loss PL_(LPN) ^(dB).

Thereafter, an uplink path loss of an uplink signal issued by the userequipment which takes the low power node as the target receiving node(which is referred to as “an uplink path loss of the low power node”hereinafter) may be further estimated based on the coordination downlinkpath loss ƒ(PL_(LPN) ^(dB)) of the low power node, for example,according to the characteristic of reciprocity between an uplink channeland a downlink channel.

In a case where the CoMP transmission mode is the single frequencynetwork coordination mode (i.e. the CoMP scenario 4), further estimationof an uplink path loss of the macro base station based on the estimatedcoordination downlink path loss ƒ(PL_(LPN) ^(dB)) of the low power nodemay be performed with the following expression (6):

TxPower(Macro_CRS)^(dB)−PL_(macro)^(dB)+TxPower(LPN_CRS)^(dB)−ƒ(PL_(LPN) ^(dB))=10 log 10(RSRP_(macro+LPN)^(Linear)(CRS))  (6)

where TxPower(Macro_CRS)^(dB) indicates transmission power in dB whenthe macro base station cooperatively transmits a CRS;PL_(macro) ^(dB) indicates a path loss of the macro base station in dB;TxPower(LPN_CRS)^(dB) indicates transmission power in dB when the LPN(Low Power Node) cooperatively transmits the CRS; and10 log 10RSRP_(macro+LPN) ^(Linear)(CRS) indicates linearly detectedRSRP of the CRS of the macro base station and the low power node.

Specifically, the estimated coordination downlink path loss ƒ(PL_(LPN)^(dB)) of the low power node may be firstly subtracted from transmissionpower TxPower(LPN_CRS)^(dB) when the low power node transmits a CRS inthe CoMP transmission mode, to obtain receiving power of the low powernode.

Further, the receiving power of the low power node may be subtractedfrom the linearly detected RSRP 10 log 10RSRP_(macro+LPN) ^(Linear)(CRS)of the CRS of the low power node and the macro base station, to obtainreceiving power of the macro base station.

Further, the receiving power of the macro base station may be subtractedfrom transmission power TxPower(Macro_CRS)^(dB) when the macro basestation transmits the CRS in the CoMP transmission mode, to obtain acoordination downlink path loss PL_(macro) ^(dB) of the macro basestation.

Finally, an uplink path loss of the macro base station may be estimatedbased on the coordination downlink path loss PL_(macro) ^(dB) of themacro base station according to the reciprocity between an uplinkchannel and a downlink channel. For example, with reference to theexpressions (2) to (5) mentioned above, the path loss PL therein isreplaced with PL_(macro) ^(dB), and then an uplink transmission powervalue of the PUSCH/PUCCH/SRS of the closed-loop power control and anuplink transmission power value of the open-loop power control may bederived.

In a case where the CoMP transmission is the independent cell IDcoordination mode (i.e., the CoMP scenario 3), further estimation of anuplink path loss of the macro base station based on the estimatedcoordination downlink path loss ƒ(PL_(LPN) ^(dB)) of the low power nodemay be performed with the following expression (7):

TxPower(Macro_CRS)^(dB)−PL_(macro)^(dB)+TxPower(LPN_Data/LPN_CSI)^(dB)−ƒ(PL_(LPN) ^(dB))=10 log10(RSRP_(macro+LPN) ^(Linear)(CRS))  (7)

where TxPower(Macro_CRS)^(dB) indicates transmission power in dB whenthe macro base station cooperatively transmits a CRS;PL_(macro) ^(dB) indicates a path loss of the macro base station in dB;TxPower(LPN_Data/LPN_CSI)^(dB) indicates transmission power in dB whenthe LPN (Low Power Node) cooperatively transmits a data signal or aCSI-RS (Channel State Information-Reference Signal); and10 log 10RSRP_(macro+LPN) ^(Linear)(CRS) indicates linearly detectedRSRP of the CRS of the macro base station and the low power node.

Specifically, the estimated coordination downlink path loss ƒ(PL_(LPN)^(dB)) of the low power node may be firstly subtracted from transmissionpower TxPower(LPN_Data/LPN_CSI)^(dB) when the low power node transmits adata signal or a CSI-RS in the CoMP transmission mode, to obtainreceiving power of the low power node.

Further, the receiving power of the low power node may be subtractedfrom the linearly detected RSRP 10 log 10RSRP_(macro+LPN) ^(Linear)(CRS)of the CRS of the low power node and to the macro base station, toobtain receiving power of the macro base station.

Further, the receiving power of the macro base station may be subtractedfrom transmission power TxPower(Macro_CRS)^(dB) when the macro basestation transmits the CRS in the CoMP transmission mode, to obtain acoordination downlink path loss PL_(macro) ^(dB) of the macro basestation.

Finally, an uplink path loss of the macro base station may be estimatedbased on the coordination downlink path loss PL_(macro) ^(dB) of themacro base station according to the reciprocity between an uplinkchannel and a downlink channel. For example, with reference to theexpressions (2) to (5) mentioned above, the path loss PL therein isreplaced with PL_(macro) ^(dB), and then an uplink transmission powervalue of the PUSCH/PUCCH/SRS of the closed-loop power control and anuplink transmission power value of the open-loop power control may bederived.

It should be understood that, in the above expression (7),TxPower(Macro_CRS)^(dB)−PL_(macro) ^(dB) indicates the power that themacro base station transmits the CRS to a terminal (receiving power ofthe macro base station), and TxPower(LPN_Data/LPN_CSI)_(dB)−ƒ(PL_(LPN)^(dB)) indicates the power that the low power node transmits the datasignal or the CSI-RS to the terminal (receiving power of the low powernode). The linearly detected RSRP 10 log 10RSRP_(macro+LPN)^(Linear)(CRS) of the CRS of the low power node and the macro basestation may be obtained by adding the two power values described above.

However, in the calculation of the linearly detected RSRP 10 log10RSRP_(macro+LPN) ^(Linear)(CRS) of the CRS of the low power node andthe macro base station, the receiving power of the macro base stationand the receiving power of the low power node may offset each other, inaddition to mutual superimposition. In a case where the receiving powerof the macro base station and the receiving power of the low power nodeoffset each other, the uplink path loss of the macro base station may beestimated with the following expression (8):

TxPower(Macro_CRS)_(dB)−PL_(macro)^(dB)−(TxPower(LPN_Data/LPN_CSI)^(dB)−ƒ(PL_(LPN) ^(dB)))=10 log10(RSRP_(macro+LPN) ^(Linear)(CRS))  (8)

In the above expression (8), nothing changes except that the signbetween the receiving power of the macro base station and the receivingpower of the low power node is changed from a plus sign to a minus sign.

In specific calculation, the estimated coordination downlink path lossƒ(PL_(LPN) ^(dB)) of the low power node may also be firstly subtractedfrom transmission power TxPower(LPN_Data/LPN_CSI)^(dB) when the lowpower node transmits a data signal or a CSI-RS in the CoMP transmissionmode, to obtain receiving power of the low power node.

Further, the linearly detected RSRP 10 log 10RSRP_(macro+LPN)^(Linear)(CRS) of the CRS of the low power node and the macro basestation may be added the receiving power of the low power node, toobtain receiving power of the macro base station.

Further, the receiving power of the macro base station may be subtractedfrom transmission power TxPower(Macro_CRS)^(dB) when the macro basestation transmits the CRS in the CoMP transmission mode, to obtain acoordination downlink path loss PL_(macro) ^(dB) of the macro basestation.

Finally, an uplink path loss of the macro base station may be estimatedbased on the coordination downlink path loss PL_(macro) ^(dB) of themacro base station according to the reciprocity between an uplinkchannel and a downlink channel. For example, with reference to theexpressions (2) to (5) mentioned above, the path loss PL therein isreplaced with PL_(macro) ^(dB), and then an uplink transmission powervalue of the PUSCH/PUCCH/SRS of the closed-loop power control and anuplink transmission power value of the open-loop power control may alsobe derived.

The above expression (8) describes a case that the receiving power ofthe macro base station and the receiving power of the low power nodeoffset each other and the receiving power of the macro base station islarger than the receiving power of the low power node. For a case thatthe receiving power of the macro base station and the receiving power ofthe low power node offset each other and the receiving power of themacro base station is not larger than the receiving power of the lowpower node, the uplink path loss may be estimated with the followingexpression (9):

TxPower(LPN_Data/LPN_CSI)^(dB)−ƒ(PL_(LPN)^(dB))−(TxPower(Macro_CRS)^(dB)−PL_(macro) ^(dB))=10 log10(RSRP_(macro+LPN) ^(Linear)(CRS))  (9)

In specific calculation, the estimated coordination downlink path lossƒ(PL_(LPN) ^(dB)) of the low power node may also be firstly subtractedfrom transmission power TxPower(LPN_Data/LPN_CSI)^(dB) when the lowpower node transmits a data signal or a CSI-RS in the CoMP transmissionmode, to obtain receiving power of the low power node.

Further, the linearly detected RSRP 10 log 10RSRP_(macro+LPN)^(Linear)(CRS) of the CRS of the low power node and the macro basestation may be subtracted from the receiving power of the low powernode, to obtain receiving power of the macro base station.

Further, the receiving power of the macro base station may be subtractedfrom transmission power TxPower(Macro_CRS)^(dB) when the macro basestation transmits the CRS in the CoMP transmission mode, to obtain acoordination downlink path loss PL_(macro) ^(dB) of the macro basestation.

Finally, an uplink path loss of the macro base station may be estimatedbased on the coordination downlink path loss PL_(macro) ^(dB) of themacro base station according to the reciprocity between an uplinkchannel and a downlink channel. For example, with reference to theexpressions (2) to (5) mentioned above, the path loss PL therein isreplaced with PL_(macro) ^(dB), and then an uplink transmission powervalue of the PUSCH/PUCCH/SRS of the closed-loop power control and anuplink transmission power value of the open-loop power control may alsobe derived.

According to the embodiments of the disclosure, under the heterogeneousnetwork scenario and in a case where common baseband processing isperformed between the low is power transmission node and the macro basestation, when the carrier aggregation is performed between basestations, the uplink PUCCH/PUSCH transmission is transmitted on theaggregated carriers of the low power transmission node as far aspossible. If the CoMP transmission is performed between the macro basestation and the low power node and uplink data transmission (includingthe PUCCH, the PUSCH, the SRS and so on) needs to be performed, then thepath loss of the low power node on a multi-point transmission frequencyhand is predicted with reference to the path loss where the low powernode separately transmits a carrier, thereby obtaining path losscompensation values of the uplink power control of a macro base stationnode and the low power node, to perform more accurate uplink powercontrol.

A wireless communication system according to an embodiment of thedisclosure is described hereinafter in conjunction with FIG. 6. As shownin FIG. 6, the wireless communication system 100 according to anembodiment of the disclosure includes a macro base station 210, a lowpower node 220, and a wireless communication device 300. The low powernode 220 and the macro base station 210 are in common baseband, and thewirclcss communication device 300 may communicate with the low powernode 220 and the macro base station 210 via multiple component carriers.

The wireless communication device 300 may include a receiving unit 310,a transmitting unit 320, a control unit 330 and the like.

The receiving unit 310 may be used to receive a downlink signaltransmitted by the low power node 220 and the macro base station 210.

The transmitting unit 320 may be used to transmit uplink signals to thelow power node 220 and the macro base station 210.

The control unit 330 may be used to control the transmitting unit 320 totransmit all of first uplink signals of the uplink signals to the lowpower node 220 as a receiving node.

The first uplink signals here may include PUCCH signal and/or PUSCHsignal.

Carrier aggregation may be performed between the low power node 220 andthe macro base station 210, and the macro base station 210 may set adownlink component carrier thereof as a downlink primary componentcarrier.

In a case where the carrier aggregation is performed between the lowpower node 220 and the macro base station 210, the control unit 330 mayrelease the association between an uplink primary component carrier andthe downlink primary component carrier.

In the FDD mode, the control unit 330 may set an uplink componentcarrier of the low power node 220 as the uplink primary componentcarrier.

The wireless communication system 100 may also be a TDD system. In thiscase, a transmission function of the downlink primary component carriermay be performed by a downlink timeslot of a component carrier of themacro base station 210, and a transmission function of the uplinkprimary component carrier may be performed by an uplink timeslot of acomponent carrier of the low power node 220.

The macro base station 210 may inform the wireless communication device300 of the uplink primary component carrier on the low power node 220 orrecovery of the association between the uplink primary component carrierand the downlink primary component carrier via RRC signaling, MACsignaling or DCI of physical layer.

The receiving unit 310 may receive the RRC signaling, the MAC signalingor the DCI of the physical layer, to know the uplink primary componentcarrier on the low power node 220. Alternatively, in a case where thewireless communication device 300 aggregates multiple component carrierson the low power node 220 and the macro base station 210 does notoperate on these component carriers, the control unit 330 may select bydefault a component carrier with highest or lowest frequency point fromthese component carriers as the uplink primary component carrier on thelow power node 220.

When the carrier aggregation between the low power node 220 and themacro base station 210 is terminated, the receiving unit 310 may alsoreceive the RRC signaling, the MAC signaling or the DCI of the physicallayer, to know recovery of the association between the uplink primarycomponent carrier and the downlink primary component carrier.Alternatively, the control unit 330 may also recover by default theassociation between the uplink primary component carrier and thedownlink primary component carrier. After the association between theuplink primary component carrier and the downlink primary componentcarrier is recovered, an uplink component carrier of the macro basestation 210 may be set as the uplink primary component carrier.

The macro base station 210 and the low power node 220 may perform CoMPtransmission on a first component carrier, and the low power node 220may also communicate with the wireless communication device 300 via asecond component carrier. In this case, the wireless communicationdevice 300 may further include an estimating unit 340 to estimate anuplink path loss of an uplink signal issued by the wirelesscommunication device 300 which takes the low power node 220 or the macrobase station 210 as a target receiving node, thereby performing uplinksignal transmission power compensation.

Specifically, the estimating unit 340 may be used to estimate acoordination downlink path loss when the low power node 220 performs theCoMP transmission for the wireless communication device 300 on the firstcomponent carrier, with reference to a separate downlink path lossoccurring when the low power node 220 transmits a downlink signalseparately for the wireless communication device 300 on the secondcomponent carrier. Then, based on the coordination downlink path loss ofthe low power node 220, the estimating unit 340 may also estimate anuplink path loss of an uplink signal issued by the wirelesscommunication device 300 which takes the low power node 220 as thetarget receiving node, to perform the uplink signal transmission powercompensation.

Further, the estimating unit 340 may be used to estimate a coordinationdownlink path loss when the macro base station 210 performs the CoMPtransmission for the wireless communication device 300 on the firstcomponent carrier based on the coordination downlink path loss of thelow power node 220. Then, based on the coordination downlink path lossof the macro base station 210, the estimating unit 340 may also estimatean uplink path loss of an uplink signal issued by the wirelesscommunication device 300 which takes the macro base station 210 as atarget receiving node, to perform the uplink signal transmission powercompensation.

Various specific embodiments of each unit described above of thewireless communication system according to the embodiment of thedisclosure have been described in detail hereinbefore, which are notrepeated here.

Obviously, each operation process of the method for performing wirelesscommunication in a wireless communication system according to thedisclosure may be implemented with a computer executable program storedin various machine readable storage mediums.

Further, the object of the disclosure may be implemented in a way that:a storage medium storing the above executable program code is directlyor indirectly provided to a system or an apparatus, and a computer or aCPU (Central Processing Unit) in the system or the apparatus reads andperforms the above program code. In this case, provided that the systemor the apparatus has a function of performing a program, then theembodiment of the disclosure is not limited to the program, and theprogram may be in any form, such as an object program, a programexecuted by an interpreter or a script program provided to an operatingsystem.

These machine readable storage mediums described above include but notlimited to various memories and memory cells, semiconductor apparatuses,disk units (such as an optical disk, a magnetic disk and amagneto-optical disk), and other mediums suitable for storinginformation.

In addition, the technical solution of the disclosure may also beimplemented by connecting a computer to a corresponding website oninternet, loading and mounting a computer program code according to thedisclosure into the computer, and then performing the program.

FIG. 7 is a block diagram of an exemplary structure of a general-purposepersonal computer in which a method for performing wirelesscommunication in a wireless communication system according to anembodiment of the disclosure can be implemented.

As shown in FIG. 7, a CPU (Central Processing Unit) 1301 performsvarious processing in accordance with a program stored in a ROM(Read-Only Memory) 1302 or a program loaded from a storage section 1308into a RAM (Random Access Memory) 1303. In the RAM 1303, data requiredwhen the CPU 1301 performs various processing is also stored asnecessary. The CPU 1301, the ROM 1302 and the RAM 1303 are connectedwith each other via a bus 1304. An input/output interface 1305 is alsoconnected to the bus 1304.

The following components are connected to the input/output interface1305: an input section 1306 (including a keyboard, a mouse and thelike), an output section 1307 (including a display (such as a CRT(Cathode-Ray Tube) and a LCD (Liquid Crystal Display)), a speaker andthe like), a storage section 1308 (including a hard disk and the like)and a communication section 1309 (including a network interface cardsuch as a LAN (Local Area Network) card, a modem and the like). Thecommunication section 1309 performs communication processing via anetwork such as internet. A driver 1310 may also be connected to theinput/output interface 1305 as necessary. A removable medium 1311, suchas a magnetic disk, an optical disk, a magneto-optical disk and asemiconductor memory, may be mounted onto the driver 1310 as necessary,so that a computer program read from the removable medium 1311 may beinstalled into the storage section 1308 as necessary.

In a case where a series of processing described above is implemented bysoftware, programs constituting the software may be installed from anetwork such as internet or a storage medium such as the removablemedium 1311.

It should be understood by those skilled in the art that, the storagemedium is not limited to the removable medium 1311 shown in FIG. 7 whichstores a program therein and distributes the program separately from theapparatus to provide the program to a user. Examples of the removablemedium 1311 include a magnetic disk (including a floppy disk (registeredmark)), an optical disk (including a CD-ROM (Compact Disc Read OnlyMemory) and a DVD (Digital Versatile Disk)), a magneto-optical disk(including a MD (Mini Disk) (registered mark)) and a semiconductormemory. Alternatively, the storage medium may be a hard disk included inthe ROM 1302 or the storage section 1308 and the like, which stores aprogram therein and is distributed to the user together with theapparatus in which the storage medium is included.

(1) A method for performing wireless communication in a wirelesscommunication system, the wireless communication system comprising a lowpower node and a macro base station with common baseband and a userequipment, the user equipment communicating with the low power node andthe macro base station via a plurality of component carriers, and themethod comprising: receiving, by the user equipment, a downlink signaltransmitted by the low power node and the macro base station; andtransmitting uplink signals to the low power node and the macro basestation, wherein the method further comprises: transmitting all of firstuplink signals of the uplink signals to the low power node as areceiving node.

(2) The method according to (1), wherein the first uplink signalsinclude a Physical Uplink Control Channel (PUCCH) signal and/or aPhysical Uplink Shared Channel (PUSCH) signal.

(3) The method according to (1) or (2), wherein carrier aggregation isperformed between the low power node and the macro base station, and themacro base station sets a downlink component carrier of the macro basestation as a downlink primary component carrier.

(4) The method according to any one of (1) to (3), further comprising:releasing association between an uplink primary component carrier andthe downlink primary component carrier.

(5) The method according to any one of (1) to (4), wherein the wirelesscommunication system is a Frequency Division Duplex (FDD) system, andthe method further comprises: setting an uplink component carrier of thelow power node as the uplink primary component carrier.

(6) The method according to any one of (1) to (4), wherein the wirelesscommunication system is a Time Division Duplex (TDD) system, atransmission function of the downlink primary component carrier isperformed by a downlink timeslot of a component carrier of the macrobase station, and a transmission function of the uplink primarycomponent carrier is performed by an uplink timeslot of a componentcarrier of the low power node.

(7) The method according to any one of (4) to (6), further comprising:knowing the uplink primary component carrier on the low power node byreceiving Radio Resource Control (RRC) signaling, Media Access Control(MAC) signaling or Downlink Control Information (DCI) of physical layer.

(8) The method according to any one of (4) to (7), wherein in a casewhere the user equipment aggregates the plurality of component carrierson the low power node and the macro base station does not operate on theplurality of component carriers, the method further comprises: knowingthe uplink primary component carrier on the low power node by receivingRRC signaling, MAC signaling or DCI of physical layer; or selecting bydefault a component carrier with highest or lowest frequency point fromthe plurality of component carriers as the uplink primary componentcarrier on the low power node.

(9) The method according to any one of (4) to (7), wherein when thecarrier aggregation between the low power node and the macro basestation is terminated, the method further comprises: knowing recovery ofthe association between the uplink primary component carrier and thedownlink primary component carrier by receiving RRC signaling, MACsignaling or DCI of physical layer; or recovering by default theassociation between the uplink primary component carrier and thedownlink primary component carrier, wherein an uplink component carrierof the macro base station is set as the uplink primary component carrierafter the association between the uplink primary component carrier andthe downlink primary component carrier is recovered.

(10) The method according to any one of (1) to (9), wherein the macrobase station and the low power node perform Coordinated Multi-Point(CoMP) transmission on at least a first component carrier, and the lowpower node further communicates with the user equipment via at least asecond component carrier.

(11) The method according to any one of (1) to (10), further comprising:estimating a first coordination downlink path loss when the low powernode performs the CoMP transmission for the user equipment on the firstcomponent carrier, with reference to a separate downlink path lossoccurring when the low power node transmits a downlink signal separatelyfor the user equipment on the second component carrier; and estimating,based on the first coordination downlink path loss, a first uplink pathloss of an uplink signal issued by the user equipment which takes thelow power node as a target receiving node on the first componentcarrier, to perform uplink signal transmission power compensation.

(12) The method according to anyone of (1) to (11), wherein the separatedownlink path loss is obtained in accordance with transmission powerwhen the low power node transmits a Cell-Specific Reference Signal (CRS)separately and a linearly detected Reference Signal Receiving Power(RSRP) of the CRS of the low power node.

(13) The method according to (12), further comprising: estimating asecond coordination downlink path loss when the macro base stationperforms the CoMP transmission for the user equipment on the firstcomponent carrier, based on the first coordination downlink path loss;and estimating, based on the second coordination downlink path loss, asecond uplink path loss of an uplink signal issued by the user equipmentwhich takes the macro base station as a target receiving node on thefirst component carrier, to perform the uplink signal transmission powercompensation.

(14) The method according to (13), wherein first receiving power isobtained in accordance with transmission power when the low power nodetransmits a CRS, data or a Channel State Information-Reference Signal(CSI-RS) in the CoMP transmission mode for the user equipment on thefirst component carrier and the first coordination downlink path loss,second receiving power is obtained in accordance with linearly detectedRSRP of the CRS of the low power node and the macro base station and thefirst receiving power, and the second coordination downlink path loss isobtained in accordance with transmission power when the macro basestation transmits the CRS in the CoMP transmission mode for the userequipment on the first component carrier and the second receiving power.

(15) The method according to (13) or (14), wherein the uplink signalissued by the user equipment which takes the macro base station as thetarget receiving node includes a Sounding Reference Signal (SRS).

(16) A wireless communication device, adapted to communicate with a lowpower node and a macro base station with common baseband via a pluralityof component carriers, the wireless communication device comprising: areceiving unit adapted to receive a downlink signal transmitted by thelow power node and the macro base station; a transmitting unit adaptedto transmit uplink signals to the low power node and the macro basestation; and a control unit adapted to control the transmitting unit totransmit all of first uplink signals of the uplink signals to the lowpower node as a receiving node.

(17) The wireless communication device according to (16), wherein thefirst uplink signals include a PUCCH signal and/or a PUSCH signal.

(18) The wireless communication device according to (16) or (17),wherein in a case where carrier aggregation is performed between the lowpower node and the macro base station, the control unit releasesassociation betwccn an uplink primary component carrier and a downlinkprimary component carrier.

(19) The wireless communication device according to any one of (16) to(18), wherein the control unit sets an uplink component carrier of thelow power node as the uplink primary component carrier.

(20) The wireless communication device according to any one of (16) to(19), wherein the receiving unit receives RRC signaling, MAC signalingor DCI of physical layer, to know the uplink primary component carrieron the low power node or recovery of the association between the uplinkprimary component carrier and the downlink primary component carrier.

(21) The wireless communication device according to any one of (16) to(20), wherein in a case where the wireless communication deviceaggregates the plurality of component carriers on the low power node andthe macro base station does not operate on the plurality of componentcarriers, the control unit selects by default a component carrier withhighest or lowest frequency point from the plurality of componentcarriers as the uplink primary component carrier on the low power node.

(22) The wireless communication device according to any one of (16) to(20), wherein when the carrier aggregation between the low power nodeand the macro base station is terminated, the control unit recovers bydefault the association between the uplink primary component carrier andthe downlink primary component carrier.

(23) The wireless communication device according to (16), wherein in acase where the macro base station and the low power node perform CoMPtransmission on a first component carrier and the low power node furthercommunicates with the wireless communication device via a secondcomponent carrier, the wireless communication device further comprisesan estimating unit configured to: estimate a first coordination downlinkpath loss when the low power node performs the CoMP transmission for thewireless communication device on the first component carrier, withreference to a separate downlink path loss occurring when the low powernode transmits a downlink signal separately for the wirelesscommunication device on the second component carrier; and estimate,based on the first coordination downlink path loss, a first uplink pathloss of an uplink signal issued by the wireless communication devicewhich takes the low power node as a target receiving node, to performuplink signal transmission power compensation.

(24) The wireless communication device according to (23), wherein theestimating unit is further configured to: estimate a second coordinationdownlink path loss when the macro base station performs the CoMPtransmission for the wireless communication device on the firstcomponent carrier, based on the first coordination downlink path loss;and estimate, based on the second coordination downlink path loss, asecond uplink path loss of an uplink signal issued by the wirelesscommunication device which takcs the macro base station as a targetreceiving node, to perform the uplink signal transmission powercompensation.

(25) A wireless communication system comprising: a macro base station; alow power node in common baseband with the macro base station; and awireless communication device according to any one of (16) to (24) whichcommunicates with the low power node and the macro base station via aplurality of component carriers.

(26) The wireless communication system according to (25), wherein themacro base station informs the wireless communication device of anuplink primary component carrier on the low power node or recovery ofassociation between an uplink primary component carrier and a downlinkprimary component carrier via RRC signaling, MAC signaling or DCI ofphysical layer.

(1) A communication device operational in a communication systemincluding a first node and a second node in common baseband with eachother, the communication device comprising: circuitry configured tocause carrier aggregation between the first node and the second nodewith the first node and the second node in common baseband with eachother, the carrier aggregation including: setting a downlink componentcarrier associated with the first node as a downlink primary componentcarrier, and setting an uplink component carrier associated with thesecond node as an uplink primary component carrier.

(2) The device according to (1), wherein the carrier aggregationincludes transmitting, using the circuitry, at least one of uplinkcontrol signaling and data packets via the uplink primary componentcarrier associated with the second node.

(3) The device according to (1) or (2), wherein the carrier aggregationincludes, prior to said setting the uplink component carrier, releasingassociation of the downlink primary component carrier from the uplinkprimary component carrier.

(4) The device according to any one of (1) to (3), wherein the firstnode is a macro base station and the second node is a low power node(LPN).

(5) The device according to any one of (1) to (4), wherein the firstnode operates at a first frequency and the second node operates at asecond frequency greatcr than the first frequency.

(6) The device according to any one of (1) and (3) to (5), wherein thecarrier aggregation includes transmitting, using the circuitry, uplinkcontrol signaling via the uplink primary component carrier associatedwith the second node to control transmissions between the device and thefirst node.

(7) The device according to any one of (1) to (6), wherein the carrieraggregation includes receiving, by the circuitry, designationinformation regarding the uplink primary component carrier via one ofRadio Resource Control (RRC) signaling, Media Access Control (MAC)signaling, or physical layer signaling.

(8) The device according to any one of (1) to (6), wherein the carrieraggregation includes aggregating multiple component carriers for thesecond node, and receiving, by the circuitry, information regardingdesignation of the uplink primary component carrier via one of RadioResource Control (RRC) signaling, Media Access Control (MAC) signaling,or physical layer signaling.

(9) The device according to any one of (1) to (8), wherein the carrieraggregation includes transmitting, using the circuitry, at least one ofPhysical Uplink Control Channel (PUCCH) signals and Physical UplinkShared Channel (PUSCH) signals via the uplink primary component carrierassociated with the second node.

(10) The device according to any one of (1) to (8), wherein the carrieraggregation includes transmitting, using the circuitry, all uplinkcontrol signaling via the uplink primary component carrier associatedwith the second node.

(11)_A wireless communication method comprising: performing carrieraggregation, using a processor, between a first node and a second nodewith the first node and the second node in common baseband with eachother, said carrier aggregation including: setting a downlink componentcarrier associated with the first node as a downlink primary componentcarrier, and setting an uplink component carrier associated with thesecond node as an uplink primary component carrier.

(12) The wireless communication method according to (11), wherein thecarrier aggregation includes transmitting uplink control signaling viathe uplink primary component carrier associated with the second node tocontrol transmissions between the processor and the first node.

(13) The wireless communication method according to (11) or (12),wherein the carrier aggregation includes receiving designationinformation regarding the uplink primary component carrier via one ofRadio Resource Control (RRC) signaling, Media Access Control (MAC)signaling, or physical layer signaling.

(14) A wireless communication device for controlling uplink transmissionpower for Coordinate Multi-Point (CoMP) transmission of a first node anda second node on a first component carrier at a first frequency, thedevice comprising: circuitry configured to receive a downlink signalfrom the second node on a second component carrier at a second frequencydifferent from the first frequency, determine a first downlink path lossassociated with receipt of the downlink signal from the second node onthe second component carrier at the second frequency, estimate a seconddownlink path loss associated with the second node performing the CoMPtransmission on the first component carrier at the first frequency basedon the determined first downlink path loss, and estimate a first uplinkpath loss of a first uplink signal output from the device to the secondnode on the first component carrier at the first frequency based on theestimated second downlink path loss, to compensate uplink signaltransmission power for the CoMP transmission.

(15) The device according to (14), wherein the uplink signal is one of aPhysical Uplink Control Channel (PUCCH) signal, Physical Uplink SharedChannel (PUSCH) signal, and a Sounding Reference Signal (SRS).

(16) The device according to (14) or (15), wherein the circuitry isconfigured to compensate the uplink signal transmission power for CoMPtransmission to the second node on the first component carrier at thefirst frequency based on the first uplink path loss.

(17) The device according to any one of (14) to (16), wherein thecircuitry is configured to compensate uplink signal transmission powerfor CoMP transmission to the first node on the first component carrierat the first frequency based on determination of a third downlink pathloss associated with receipt of a downlink signal from the first node onthe first component carrier at the first frequency, and determination ofa second uplink path loss of a second uplink signal output from thedevice to the first node on the first component carrier at the firstfrequency based on the third downlink path loss.

(18) The device according to any one of (14) to (17), when the CoMPtransmission of the first node and the second node is according to CoMPscenario 4, receiving power associated with the first node is obtainedby adding linearly detected reference signal receiving power ofcell-specific reference signal of the first and second nodes toreceiving power associated with the second node.

(19) The device according to any one of (14) to (17), wherein, when theCoMP transmission of the first node and the second node according toCoMP scenario 3, receiving power associated with the first node isobtained by subtracting linearly detected reference signal receivingpower of cell-specific reference signal of the first and second nodesfrom receiving power associated with the second node.

(20) A wireless communication method for controlling uplink transmissionpower for Coordinate Multi-Point (CoMP) transmission of a first node anda second node on a first component carrier at a first frequency, themethod comprising: receiving a downlink signal from the second node on asecond component carrier at a second frequency different from the firstfrequency, determining a first downlink path loss associated withreceipt of the downlink signal from the second node on the secondcomponent carrier at the second frequency, estimating a second downlinkpath loss associated with the second node performing the CoMPtransmission on the first component carrier at the first frequency basedon the determined first downlink path loss, and estimating a firstuplink path loss of a first uplink signal output from the device to thesecond node on the first component carrier at the first frequency basedon the estimated second downlink path loss, to compensate uplink signaltransmission power for the CoMP transmission.

Obviously, in the system and the method of the disclosure, individualcomponents or individual steps may be decomposed and/or recombined.These decompositions and/or recombinations should be considered asequivalent solutions of the disclosure. Further, the steps forperforming the series of processing described above may be performednaturally in time sequence illustrated herein, but are not necessary tobe performed in the time sequence. Some steps may be performed inparallel or independently of each other.

Although the embodiments of the disclosure have been described above indetail in conjunction with the accompanying drawings, it should beunderstood that, embodiments described above are only used forillustrating the disclosure, rather than limiting the disclosure.Various modifications and variants may be made to the above embodimentsby those skilled in the art without deviation from the spirit and scopeof the disclosure. Therefore, the scope of the disclosure is onlydefined by the appended claims and the equivalents thereof.

1. A communication device operational as a first node in a communicationsystem including a user terminal and a second node, the communicationdevice comprising: circuitry configured to cause communication with theuser terminal with multiple component carriers, the communicationincluding: obtaining a downlink component carrier as a downlink primarycomponent carrier for communication with the user terminal, changing thedownlink primary component carrier only in a condition of a handover,obtaining an uplink component carrier for receiving a Physical UplinkControl Channel (PUCCH) from the user terminal, and transmitting, viaRadio Resource Control (RRC) signaling, designation informationregarding an uplink primary component carrier to override an uplinkprimary component carrier set as a default uplink primary componentcarrier by the user terminal.
 2. The device according to claim 1,wherein the circuitry is further configured to transmit PUCCH signals onthe uplink component carrier.
 3. The device according to claim 1,wherein the first node is a macro base station and the second node is alow power node.
 4. The device according to claim 3, wherein thecircuitry is further configured to obtain the second node as the defaultuplink primary component carrier.
 5. The device according to claim 3,wherein the circuitry is further configured to obtain the first node asthe default uplink primary component carrier.
 6. The device according toclaim 3, wherein the circuitry is further s configured to receive PUCCHsignals on both of an uplink component carrier associated with thesecond node and an uplink component carrier associated with the firstnode.
 7. The device according to claim 1, wherein the uplink primarycomponent carrier is associated with a different node than the downlinkprimary component carrier.
 8. The device according to claim 1, whereinthe first node operates at a first frequency and the second nodeoperates at a second frequency higher than the first frequency.
 9. Thedevice according to claim 1, wherein the circuitry is further configuredto receive uplink control signaling via the uplink component carrier tocontrol transmissions between the user terminal and the first node. 10.The device according to claim 1, wherein the first node and the secondnode are in common baseband with each other.
 11. A communication deviceoperational as a user terminal in a communication system including afirst node and a second node, the communication device comprising:circuitry configured to cause communication with the first and secondnodes with multiple component carriers, the communication including:setting a downlink component carrier associated with a first node as adownlink primary component carrier, changing the downlink primarycomponent carrier only in a condition of a handover, setting an uplinkcomponent carrier for receiving a Physical Uplink Control Channel(PUCCH) from the user terminal, and receiving, via Radio ResourceControl (RRC) signaling, designation information regarding an uplinkprimary component carrier to override an uplink primary componentcarrier set as a default uplink primary component carrier by the userterminal.
 12. The device according to claim 11, wherein the circuitry isfurther configured to transmit PUCCH signals on the uplink componentcarrier.
 13. The device according to claim 11, wherein the first node isa macro base station and the second node is a low power node.
 14. Thedevice according to claim 13, wherein the circuitry is furtherconfigured to set the second node as the default uplink primarycomponent carrier.
 15. The device according to claim 13, wherein thecircuitry is further configured to set the first node as the defaultuplink primary component carrier.
 16. The device according to claim 13,wherein the circuitry is further configured to transmit PUCCH signals onboth of an uplink component carrier associated with the second node andan uplink component carrier associated with the first node.
 17. Thedevice according to claim 11, wherein the uplink primary componentcarrier is associated with a different node than the downlink primarycomponent carrier.
 18. The device according to claim 11, wherein thefirst node operates at a first frequency and the second node operates ata second frequency higher than the first frequency.
 19. The deviceaccording to claim 11, wherein the circuitry is further configured toestimate an uplink path loss and perform uplink signal transmissionpower compensation.
 20. The device according to claim 11, wherein thefirst node and the second node are in common baseband with each other.